创建多个列表时指向同一个元素

Question

我需要根据这三个对象创建 3 个列表：

{"cat","owl","fish","mouse","elephant"}
{"cat","owl","fish","mouse","elephant"}
{"cat","owl","fish","mouse","elephant"}

如何节省空间使我不指定"mouse", "elephant" 3 次？对象被迭代，我事先并不知道对象包含什么。

// pseudocode

public static List<String> getValuesAsList(myCoolObjects)
    for(MyCoolObject myCoolObject: MyCoolObjects){
    List<String> listContainingObjectValues = new ArrayList<>();
       listContainingObjectvalues.add(myCoolObject.getValue1());
       listContainingObjectvalues.add(myCoolObject.getValue2());
       listContainingObjectvalues.add(myCoolObject.getValue3());
    }
    return listContaingObjectValues;

这样结果就不会是这样的：

List 1 ["cat","mouse","elephant"]
List 2 ["owl","mouse","elephant"]
List 3 ["fish","mouse","elephant"]

想要的结果是这样的：

List 1 ["cat","mouse","elephant"]
List 2 ["owl",*points to 'List 1.[1]', *points to 'List 1.[2]'*]
List 3 ["fish",*points to 'List 1.[1]', *points to 'List 1.[2]'*]

这是 Java 已经在做的事情吗？

Answer 1

假设您有一个描述第一列的列表和一个包含其余列值的列表，则可能会生成一个列表列表：

List<String> firstCol = Arrays.asList("cat", "owl", "fish");
List<String> otherCols = Arrays.asList("mouse", "elephant");
    
List<List<String>> lists = firstCol.stream()
                                   .map(col -> Stream.concat(Stream.of(col), otherCols.stream())
                                                     .collect(Collectors.toList())
                                   )
                                   .collect(Collectors.toList());

lists.stream().forEach(System.out::println);

输出：

[cat, mouse, elephant]
[owl, mouse, elephant]
[fish, mouse, elephant]